Metal Semiconductor Heterostructures for Photocatalytic Conversion of Light Energy.

For fast separation of the photogenerated charge carriers, metal semiconductor heterostructures have emerged as one of the leading materials in recent years. Among these, metal Au coupled with low bandgap semiconductors remain as ideal materials where both can absorb the solar light in the visible region. It is also established that on excitation, the plasmonic state of gold interacts with excited state of semiconductor and helps for the delocalization of the photogenerated electrons. Focusing these materials where electron transfer preferably occurs from semiconductor to metal Au on excitation, in this Perspective, we report the latest developments in the synthetic chemistry in designing such nano heterostructures and discuss their photocatalytic activities in organic dye degradation/reduction and/or photocatalytic water splitting for generation of hydrogen. Among these, materials such as Au-CZTS, Au-SnS, Au-Bi2S3, Au-ZnSe, and so forth are emphasized, and their formation chemistry as well as their photocatalytic activities are discussed in this Perspective.